


Waterlogged soul

by othersin



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Angst, Backstory, Big Brother Papyrus, Dark Fantasy, F/F, F/M, Fontcest, Gaster Has Issues, Good W. D. Gaster, Horror, Insanity, Jealously, Just don't, M/M, Mermaids, Morality, Papyrus Has Issues, Pre-Accident W. D. Gaster, Sans/Papyrus - Freeform, Scientist W. D. Gaster, Skeleton Sex (Undertale), Suicide, Underswap Muffet, Underswap Papyrus, Underswap Sans, Undertale AU, don't fuck with mermaids, fish skeleton, happiness? what is it, kinda fucking with my own characters more than gaster for once., sans is a mermaid, undertheseatale
Language: English
Status: In-Progress
Published: 2018-02-27
Updated: 2018-02-27
Packaged: 2019-03-24 16:02:48
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 1
Words: 2,090
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13814616
Author URL: https://archiveofourown.org/users/othersin/pseuds/othersin
Summary: this is going to be a short story if I can help it.W.D Gaster and his young family are happy, I mean, what do they have to unhappy about?  But when a mysterious creature finds itself trapped in the lab - Gaster finds that his happiness is only marrow deep and he ends up battling with his own sanity and morality when temptation swims his way.





	Waterlogged soul

* * *

Calibri stood there in the kitchen, her soft humming and the sound of running water was the only sound in the pristine kitchen, staring at the steadily filling sink – the lukewarm, sudsy water lapped at the metal, while her gurgling baby played idly; squeaking a fish bath toy happily.

“C’mon Papy, it’s bath time!” Calibri said, bending down and removing the child that was tugging at her floral, flared skirt – protected by an apron with lace trimmings. She placed the baby into the filling sink, the baby bones teethed at the rubber toy, the toys eyes bulged with every bite and let out a squeak.

Calibri pressed a kiss against her son’s skull – little baby hands reaching out to pat and explore the face of one that nurtured and loved him unconditionally.

“Ma!” Papyrus called to her gleefully, making Calibri giggle, at that sound the baby bones excitedly splashed happily. Little hands hitting the water and stubby legs kicking and splashing – Calibri was surely going to get drenched, but she didn’t mind, she would simply change again to look nice when her husband returned from the lab.

“My little water baby…” Calibri giggled happily, though looking at the clock quickly for the time.

* * *

 

Wing Dings Gaster found himself staring at the framed picture on his desk – and then back to the white board, filled with algorithms that even made him feel dizzy to look at, he returned his gaze back to the framed photo. His wife was sleeping by the window in the baby’s room in a wicker chair filled with a plush pillow, in her arms was the snoozing baby Papyrus – wrapped in an orange fleece blanket. He couldn’t resist from taking a picture of his two favourite monsters – Gaster stared at the clock, it was probably Papyrus’s bath time so he should probably wait a bit before calling them.

Another photo was next to that homely one, was of his entire Core team, first order of business given to the brightest monsters when they were forced underground was to restore power. The thermal power from the active volcano and steam was harnessed with much difficulty – in the picture was after they had the power running correctly without explosions or fire for once, everyone in the photo looked tired and ecstatic at the same time.

If Gaster remembered correctly, he had burst out into manic laughter making everyone concerned that the project finally broke him – only being snapped out of it when he was slapped by one of the engineers.

He was so taken by the engineer and simply ecstatic it was finally over with, that he had asked the engineer if she would like to go to Grillby’s for a drink – she accepted. And the rest was history, the feisty engineer had agreed to become his wife and now mother of his child.

Both are creators of science but if anyone would ask what was Gaster’s best creation, it would always be Papyrus first and foremost. He was certain Calibri felt the same way, she seemed happy to concentrate on looking after Papyrus and the house – at least till he was old enough to start school.

He was happy…no, content, at how this lifetime is spanning out – he truly did love them.

Gaster pulled his gaze away from the photos and back to the looming white board – letting out a forlorn sigh, trying to fall back in his work headspace. Only to be distracted by the noisy phone, semi hoping it to be Calibri excitedly telling him what cute things Papyrus did today or asking him what he would like for dinner.

“Doctor Gaster, you are needed at the reactor core tank.” The frantic voice of Alphys buzzed though the phone. Gaster blinked in confusion, the core tank? It was a large basin that was filled to the brim with water – used in case of a meltdown or if the core overheated. Thankfully they have never used it besides in drills to see if the mechanism still works, a tank that was circled though every day with pipes that lead into the core and pipes that feed in and out the water.

Maybe some seaweed was stuck in the pipes again – well, anything was better than staring at his failed algorithms.

“Is it blocked again?” Gaster asked gently.

“Well…” Alphys began to stutter, he could imagine his yellow, reptilian assistant nervously biting her lip – digging a fang in her scaled skin.

“Don’t worry Alphys, I’ll be down there in a minute.” Gaster assured the poor monster on the other side of the line, which the phone call was cut – out of the other monsters’ frantic nature. He hung up and stood, cracking his neck and stretching after from sitting down for too long. He will call Calibri after he sorts this problem out.

* * *

 

Calibri found herself staring at her crossword, after Papyrus’s bath-time, the little babe got sleepy and so she tucked the little monster for his afternoon nap – sleeping with his bath toy, the little, blue, goofy eyed fish. Calibri had long since given up on trying to get Papyrus to sleep with the fluffy bunny toy that Toriel had made for him but at least it keeps him calm doing nap-time.

It was so rare that Calibri had time for herself, she tapped her pen against the table, it was nice, she continued to tap the pen against the table. She bolted up almost too excitedly when the phone rang, the bright yellow phone hanging on the wall was almost lunged at by the female skeleton. Almost loosing her balance but quickly righting herself.

“Hello? Wing?”, Calibri said excitedly though flushing in embarrassment at voice on the other side not being who she expected.

“Sorry, were you expecting a phone call from Wing dings…” The kindly, and sweet voice of Toriel sounded though the line, “I can call back another time.”

“No, it’s okay Toriel – what did you wish to talk about?” Calibri cringed, irritated at how desperate she had seemed but continued cheerfully.

“I just wanted to see how you are getting on.” Toriel began, “I haven’t seen you or the doctor around lately.”

“What can I say, everyday is a new adventure with Papyrus and Wing Dings has been quite busy at the lab.” Calibri forced down the pang in her chest at that.

“That sounds lovely…how old is little Papyrus now?” Toriel began, though it seemed the other was trying to do the same thing too.

“He’s going to be turning one soon.” Calibri said happily.

“…” the skeleton monster was met with silence from the other end.

“Toriel?” Calibri asked.

“I’m sorry dear, just thinking about something…” That was the only answer the former queen gave.

Toriel didn’t have to say what she was thinking about, it didn’t take another mother to understand the queens pain. Calibri clenched the phone, she honestly didn’t know what she would do if anything happened to Papyrus.

What would Gaster do if anything ever happened to them? Calibri found herself ponder, she didn’t know what she wanted him to do.

“You’re more than welcome to come.” Calibri offered warmly, “Grillby was bringing food and Muffet was bringing a cake.”

“I’ll see…” Toriel said, after a while.

Calibri knew the queen would not attend if Asgore was going to be there – knowing that Wing Dings would probably invite the King, it wasn’t really her place to tell Wing not to with both the monsters history and long friendship.

“I shall visit you.” Calibri then offered, “And I’ll bring Papyrus.”

“Yes…I would like that.” Toriel did say warmly.

The little cry from Papyrus had ended the call from the queen of the monsters, Calibri excused herself and went to go upstairs to see her little baby.

Papyrus was crying and thrashing in his cacoon of blankets, Calibri went to move forward only to stop at the low squeak from under her foot – the little fish toys bulged comically when she had stepped on it. Calibri sighed and bent down to pick it up, surely the reason why Papyrus was crying at the moment.

She walked to Papyrus who had almost instantly reached for her and the familiar toy – she handed back the toy and smiled gently at the gurgling babe, teething at the rubber toy.

“Papyrus, you have to look after what you love – or you may lose it.”

Calibri never thought of how true that statement was until she said it.

* * *

 

 “Am I the only one you called Alphys?” Gaster couldn’t tear his eyes away from the shifting water, the water was foggy, sediment from the waterways made up from the dust of unfortunate monsters meeting their ends in the cool waters, sand from the riverbank and the minerals eroded from the underground caves.

Alphys wringed her hands together and nodded softly, staring transfixed at the foggy water being held in the flooding tank.

“…” Gaster walked closer to the swirling water, the water shifting and a long shadow swam at the dark depths and where the lab lights didn’t cut though that place of watery darkness.

“Let’s keep this between us.” Gaster said to his assistant, Alphys nodded hurriedly – shuffling closer to her superior and whispering,

“Doctor, what is _it_?”

A long drawn out call sounded out from the tank, almost in a musical hymn like sound to it – the sound of bones scratching against the glass was heard for a moment but then stilling suddenly.

Gaster’s sockets narrowed, and he pushed the glasses back on the bridge of his nose – it had been slipping and almost falling off. He walked closer to the tank, slowly and if Alphys pulling at his arm to stop him from getting closer but it seemed his body was moving by itself – the concerns his assistant had are surely the same ones that he had swirling in his skull.

The bubbling fear was not enough to overpower his scientific curiosity however, he raised a hand to the magic proof glass. He could feel vibrations, similar to being close or having a hand on top of a speaker – even more bizarre, he could swear he recognized the beat in the vibrations. It sounded like a lullaby you would sing to a babe who had trouble sleeping.

“Doctor!” Alphys whispered urgently to her transfixed superior pulling him a bit harder, breaking the doctors contact with the glass – making him flinch away even further, his bony hand trembled, almost as though that underwater song was still running though his hands, down his arms and into his very soul.

The shadowy figure in the water revealed themselves sensing his presence, pressing their own hands against the other side of the glass, their own bony hands webbed and shimmered in their own magic – shimmering like green fish scales in the rising sun but this time under the artificial lab lights.

The body; from their high chest, ribcage, spine was covered in the same shimmering magic as the webbing and their pelvis had instead of legs the stubby bony fins and a long, powerful looking fish tail – the shimmering magic wrapped around the strange spliced skeletal frame of both monster and fish.

The creature’s eyes burned and smouldered like the underwater volcanos, the colour was of mossy seaweed forests that tangled those who swam too deep and the sockets seemed to hold an unnaturally beautiful light within them; of that of an angler fishes hanging lure, a predator waiting within the depths. Gaster pulled his gaze from the others, feeling as though the other was stripping him bear with just one look, and looked at its full length – gaze unfortunately falling to its pelvis, trying to force back the chastising thoughts at looking there too, noting it’s width quickly before turning to the frozen yellow lizard.

“It…is a she.” Gaster finally found the answer to his assistant’s question, the yellow lizard stood their stunned – mouth gaping unable to speak but only making odd noises.

* * *

 

 A/N please drop a kudos and a comment if you liked :) and yes, I am aware that I have other stories that everyone would prefer me to update...I only got the drive back to write, due to the fact at my work i haven't been getting any shifts and now randomly getting some just now has somewhat irritated me. Anyway, if anyone wants to see the arts I do/ideas I draw for stories you can check me out on tumblr/redbubble/kofi @otherangela and on threadless @otherdesigns


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